Rate equations

This lecture covers the basics of laser operation, including light-atom interaction, Lorentz model, absorption, gain, laser systems, noise characteristics, optical fibers, ultrafast lasers, nonlinear frequency conversion, and laboratory visits. It also discusses the quantum vs classical view of the atom, stimulated emission, Doppler broadening, building blocks of a laser, cavity necessity, and resonator design. The lecture delves into the threshold condition, etalon optical transmission, and 3-level system rate equations. It concludes with the derivation of photon lifetime in the cavity and the example of a He-Ne laser.